1. Field of the Invention
The present invention relates to recording or reproduction of audio signals or the like which are read out by various types of reproduction units with fidelity to the original signals.
2. Prior Art
Recently, general music or image players having a storage medium such as a disc for readout or record thereof have been produced to be widely used. Particularly, a record and reproduction system incorporating a mini-disc (called MD hereinafter) that is a magneto-optic disc is becoming popular among users. The MD is capable of record and reproduction of music data with ease in the same way as conventional audio cassettes or the like.
To simplify the following description, a record and reproduction disc unit will be discussed as an example of an audio record MD. However, the present invention including its embodiments described later is naturally applicable to various types of discs capable of record and reproduction of image, data, or the like.
The MD is received in a cartridge in a manner similar to a 3.5 inch floppy disc mounted in a personal computer. The MD is capable of a maximum 74 minute record and reproduction like a CD (compact disc). The MD adopts a 44.1 kHz sampling frequency with 16 bit quantized signals like a CD, but utilizes a data compression art called as ATRAC (Adaptive Transform Acoustic Coding) to compress recorded data to one-fifth.
ATRAC quantizes signals by an A-D conversion like a CD, and the quantized signals are divided every predetermined time (the maximum is 11.6 ms) so as to be processed by Fourier transform processing to obtain about a thousand of frequency components (spectrum). The spectrum is separated into some zones based on a human auditory sense characteristic such as minimum audible limits (each minimum audible level corresponding to each frequency) and a masking effect (a quiet sound is not audible in a loud one). The zones are efficiently marked with codes in consideration of priority thereof.
As discussed above, the record data quantity is reduced to one-fifth based on the human auditory sense characteristic so that MD is not so much inferior to CD in audibility. Such MD having a small disc diameter is presently utilized mainly in portable units as a headphone stereo. The portable units are subject to an impulsive force due to vibration, falling, etc. because of usage during the transportation thereof. Particularly, MD discs that are storage mediums have a data record surface sensitive to a scratch caused by various reasons although they each are received in a cartridge like a 3.5 inch floppy disc.
If there is produced a deficiency (defect) such as a surface flaw on a storage medium like a disc, a sound skip and a deterioration of reproduction characteristics arise on reproduction of the storage medium. On recording, the deficiency also arises a record quality degradation due to or an error like a dropout of recorded data or a defective condition such as a repeated record operation at an area of the medium.
As described above, the conventional information record/reproduction unit has such disadvantages if there is produced a deficiency like a surface flaw on the disc.
In view of the disadvantages in the prior art, an object of the present invention is to provide an information record/reproduction unit and a method of the same, which are capable of record and reproduction of the information with a maximum fidelity to the original signals even if there is produced a defect due to a surface flaw and etc. on a storage medium such as a disc.
For achieving the object, a first aspect of the present invention is an information reproduction unit which includes:
a read means having a pickup for reading data recorded on a storage medium,
a write means for writing the data into a memory,
a reproduction means for sequentially reading out the data written in the memory, and
a detection means for detecting a defect of the storage medium storing the data before the data is read out from the storage medium.
A second aspect of the present invention is an information reproduction unit having a pickup for intermittently reading data recorded on a storage medium, a write means for writing the data in a memory, and are production means for sequentially reading out the data written in the memory. The information reproduction unit includes:
a data read means for intermittently reading the data recorded on the storage medium, and
a first defect detection means for detecting a defect of the storage medium, which stores data to be subsequently reproduced, during a read pause period of the data read means.
A third aspect of the present invention is dependent on the second aspect of the invention. Furthermore, the first defect detection means detects a defect based on a readout result of data to be reproduced next.
A fourth aspect of the present invention is dependent on the second aspect of the invention. The unit further includes:
a first storage means for storing a defect position information of the defect detected on the storage medium by the first defect detection means,
a read characteristic adjustment means for adjusting a read characteristic on reading data at the defect position, which is stored by the first storage means, on the storage medium.
A fifth aspect of the present invention is dependent on the fourth aspect of the invention. Furthermore, the read characteristic adjustment means reduces at least one of servo loop gains of a focusing servo and a tracking servo.
A sixth aspect of the present invention is dependent on the second aspect of the invention. Furthermore, the first defect detection means detects a defect of the storage medium by detecting that at least one of a RF signal, a tracking error signal, and a focusing error signal reaches a predetermined threshold level.
A seventh aspect of the present invention is an information record unit which includes:
a write means for writing data, which will be recorded on a storage medium, firstly in a memory,
a record means for recording the data, which is written in the memory, on the storage medium, and
a detection means for detecting a defect of the storage medium recording the data before the data is recorded on the storage medium.
An eighth aspect of the present invention is an information record unit for writing data firstly in a memory to intermittently record the data, which is written in the memory, on a storage medium. The unit includes:
a data record means for intermittently recording data, which is to be written on the storage medium, on the storage medium, and
a second defect detection means for detecting a defect of the storage medium to record next data during a record pause period of the data record means.
A ninth aspect of the present invention is dependent on the eighth aspect of the invention. Furthermore, the second defect detection means detects a defect based on a readout result of an area which has recorded data to be stored next by means of a data read means.
A tenth aspect of the present invention is dependent on the eighth aspect of the invention. The unit further includes a third defect detection means for detecting the extent of the defect detected by the second defect detection means.
An eleventh aspect of the present invention is dependent on the eighth aspect of the invention. The unit further includes:
a second storage means for storing a defect position, which is detected by the second defect detection means, on the storage medium, and
a record characteristic adjustment means for adjusting a record characteristic on recording data of the defect position, which is stored by the second storage mean, on the storage medium.
A twelfth aspect of the present invention is dependent on the eleventh aspect of the invention. Furthermore, the record characteristic adjustment means reduces at least one of servo loop gains of a focusing servo and a tracking servo.
A thirteenth aspect of the present invention is dependent on the tenth aspect of the invention. The unit further includes a third storage means for storing a defect position on the storage medium detected by the third defect detection means, wherein the data record means records the data on the storage medium with avoiding the defect position.
A fourteenth aspect of the present invention is dependent on the seventh aspect of the invention. Furthermore, the defect detection means detects a defect of the storage medium by detecting that at least one of a RF signal, a tracking error signal, and a focusing error signal reaches a predetermined threshold level.
A fifteenth aspect of the present invention is dependent on the seventh aspect of the invention. The unit further includes a decision means for determining whether the storage medium is a virgin record disc or not, wherein the second defect detection means detecting a defect of the storage medium based on a reflection light quantity from the storage medium where the decision means has determined that the storage medium is a virgin record disc.
A sixteenth aspect of the present invention is an information reproduction method for reading data recorded on a storage medium by means of a pickup, writing the data in a memory, and sequentially reading out the data written in the memory. The information reproduction method includes the steps of:
reading a data recorded on the storage medium from a predetermined top address of the storage medium by a read means, before next data is read out from the storage medium,
storing the read data in the memory,
detecting a defect of the storage medium based on the data stored in the memory,
storing the address of the defect position on the storage medium,
returning the read means to the predetermined top address on the storage medium, and
reducing at least one of servo loop gains of a focusing servo and a tracking servo to read the data from the predetermined top address on the storage medium by the read means when a defect is detected on the storage medium.
A seventeenth aspect of the present invention is an information reproduction method for intermittently reading data recorded on a storage medium by means of a pickup, writing the data in a memory, and sequentially reading out the data written in the memory. The information reproduction method includes the steps of:
reading a data recorded on the storage medium from a predetermined top address of the storage medium by a read means during a pause period of the data reading for the reproduction, before a next data is read out from the storage medium,
storing the read data in the memory,
detecting a defect of the storage medium based on the data stored in the memory,
storing the address of the defect position on the storage medium,
returning the read means to the predetermined top address on the storage medium during a pause period of the data readout, and
reducing at least one of servo loop gains of a focusing servo and a tracking servo to read the data from the predetermined top address on the storage medium by the read means when a defect is detected on the storage medium.
An eighteenth aspect of the present invention is an information record method for writing data, which will be recorded on a storage medium, in a memory firstly, and for recording the data, which is written in the memory, on the storage medium, the information reproduction method comprising the steps of:
reproducing of the storage medium from a predetermined top address of the storage medium by a predetermined read means before recording data on the storage medium,
storing the reproduced information in the memory,
detecting a defect of the storage medium based on the information stored in the memory,
storing the address of the defect position on the storage medium, returning the read means to the predetermined top address on the storage medium, and
adjusting a data record characteristic on recording data of the address of the defect position on the storage medium to record the data from the predetermined top address on the storage medium by the read means when a defect is detected on the storage medium.
A nineteenth aspect of the present invention is an information record method for writing data, which will be recorded on a storage medium, in a memory firstly, and for intermittently recording the data, which is written in the memory, on the storage medium, by a predetermined data record means, the information record method comprising the steps of:
reproducing of the storage medium from a predetermined top address of the storage medium by a predetermined read means during a pause period of the data recording, before recording data on the storage medium,
storing the reproduced information in the memory,
detecting a defect of the storage medium based on the information stored in the memory,
storing the address of the defect position on the storage medium,
returning the record means to the predetermined top address on the storage medium during a pause period of the data recording, and
adjusting a data record characteristic on recording data of the address of the defect position on the storage medium to record the data from the predetermined top address on the storage medium by the read means when a defect is detected on the storage medium.
Now, operational effects of the present invention will be discussed. As described above, in the present invention, a defect on the storage medium such as a disc due to a surface flaw thereof is detected before data read/record, and a read characteristic or a record characteristic is adjusted at the defect position. Thereby, during the reproduction, it is avoided that a reproduction signal contains a data deterioration like a sound skip. Furthermore, it is also avoided that the recording quality is degraded due to a dropout or a garbage of record data (signal) during recording, and a drawback such a repeated record operation of the same area will be avoided.